Our research interests concern fundamental studies on the enzymology of DNA replication and on the molecular mechanisms employed for its regulation. We have chosen the chromosome of bacteriophage lambda for model studies of these processes. Our long-range goal is to elucidate the molecular functions of the viral and host proteins which participate in the replication of lambda DNA and to illuminate the regulatory process which controls the initiation of DNA synthesis on he lambda chromosome. The primary immediate aim is to develop a soluble in vitro assay system which can support the authentic semi-conservative replication of supercoiled lambda or lambda dv DNA. It is anticipated that the successful system will contain purified host replication proteins, an extract from cells harboring lambda dv plasmids (containing excess levels of the lambda replication proteins O and P), and perhaps additional bacterial replication proteins proided by an extract from gently lysed E. coli.